Results of Transthoracic Esophagotomy Retrieval of Esophageal Foreign Body Obstructions in Dogs: 14 Cases (2000–2004)

Introduction

Esophageal foreign bodies are a common clinical problem in dogs and can become life threatening.^1–3 The most frequent type of foreign body found in dogs is ingested bone or bone fragments.^1,4,5 Other objects reported include fishhooks, hide chews, balls, and toys.^1,4,5 Foreign bodies typically lodge in one of four regions in the esophagus where there is an anatomic narrowing: namely, at the pharynx, thoracic inlet, heart base, and distal esophagus (i.e., between the heart and the diaphragm).^1,4,5 Small-breed dogs, especially terriers, are most commonly affected and are usually ≤3 years of age.^1,4–6 Clinical signs associated with esophageal foreign bodies include lethargy, anorexia, hypersalivation, retching, regurgitation, restlessness, and distress.^1,3,6

The duration of clinical signs before presentation may range from a few hours to several weeks.^1,3,6 Foreign body removal from the thoracic esophagus may be achieved by several methods.^1–3 Usually a rigid or flexible endoscope is used to withdraw the foreign body through the mouth or to advance it into the stomach for dissolution or removal via gastrotomy.³ Nonsurgical procedures are usually attempted initially.^1,2,6 Indications for surgical retrieval include an immovable foreign body and a high risk of causing or worsening perforation of the esophagus by attempting removal.³ Esophageal surgery has historically been associated with greater risk of incisional dehiscence than surgery on other portions of the alimentary tract.³

The purpose of this study is to report that surgical management can be a viable method of foreign body removal from the thoracic esophagus without increased risk of complication. The surgical technique, postoperative management, and outcomes of dogs undergoing transthoracic esophagotomy for removal of esophageal foreign bodies are reported.

Materials and Methods

The medical records of all dogs presenting with esophageal foreign body obstruction at Oakwood Veterinary Referrals (OVR), Cheshire, United Kingdom, between June 2000 and October 2004 were identified. Data from dogs that underwent transthoracic esophagotomy for removal of the esophageal foreign body were selectively reviewed for this report.

On admission, routine complete blood counts and biochemical profiles were performed. All dogs received lactated Ringer’s solution administered intravenously (IV) at a rate of 2 to 10 mL/kg per hour, and this was continued postoperatively. Dogs were anesthetized, and lateral thoracic radiographs were obtained in all cases. An endoscopic esophageal examination using a flexible and/or rigid endoscope, and attempts to remove and/or advance the foreign body into the stomach were made in all cases. When removal or advancement was not possible, lateral thoracic radiography was used to determine where to surgically incise the esophagus.

Prior to surgery, all dogs received amoxicillin/clavulanate^a (12.5 mg/kg IV). Dogs were positioned in right lateral recumbency, and a standard left intercostal thoracotomy was performed.⁷ The esophagus was identified, and branches of the vagus nerve were gently retracted from the affected site. Stay sutures^b were placed on both sides of the esophageal incision site to provide traction and stability during esophageal manipulation. Saline-soaked sponges were packed around the proposed incision site to limit contamination of the pleura. A dorsal or left lateral longitudinal incision was made in the esophagus overlying the foreign body. The foreign body was grasped, usually with Kocher forceps,^c and removed by gentle manipulation and traction. The mucosal surface of the esophageal wall was débrided as necessary and was closed using a double-layer technique. The mucosa and submucosa were closed using 3-0 or 4-0 poliglecaprone 25^d in a simple continuous suture pattern. The muscularis and adventitia were closed with 3-0 or 4-0 monofilament glycomer 631^e in a simple continuous suture pattern. When a perforation was present, the esophageal incision site and pleura were lavaged with warm saline (0.9%) after closure of the esophagotomy. An intercostal thoracostomy tube (12 to 16 French gauges) was then inserted through the thoracic wall, dorsal and caudal to the thoracotomy site. The thoracotomy was closed routinely using monofilament no. 1 polydioxanone sutures^f that were pre-placed and passed bluntly through adjacent intercostal spaces in a cruciate mattress pattern. The subcutaneous tissues and skin were closed routinely. Air and fluid were drained from the pleural cavity via the thoracostomy tube immediately after closure.

Thoracostomy tubes were removed immediately after anesthesia unless an effusion was present. Thoracostomy tubes were left in place and aspirated three times daily until the effusion resolved, and then they were removed. Effusion fluid was submitted for cytological analysis and aerobic and anaerobic bacterial culture. All dogs were fed small volumes of a prescription diet^g 12 hours postoperatively. Postoperative analgesia was accomplished with morphine^h (1 mg/kg subcutaneously [SC]) or methadoneⁱ (0.5 mg/kg SC). Some dogs required additional buprenorphine^j (0.01 mg/kg SC). Dogs were discharged from the hospital if they were eating, had no vomiting or regurgitation, and appeared pain free. The first eight dogs surviving surgery underwent a second esophageal endoscopy for assessment of the esophagotomy site.

Repeat esophagoscopy was performed at intervals ranging from 2 to 14 days postoperatively.

Follow-up data were collected by telephone conversations with the owners. No reexaminations were performed >1 month postoperatively.

Results

Fourteen dogs with thoracic esophageal foreign body obstructions were included in the study [see Table]. Four were male, and 10 were female. The mean age was 5 years (range 2 months to 13 years). Breeds included the West Highland white terrier (n=3), mixed-breed dog (n=2), Cairn terrier (n=2), Staffordshire bull terrier (n=2), bullmastiff (n=2), and one each of the golden retriever, boxer, and English cocker spaniel. History and presenting clinical signs varied between cases. In 13 cases, owners had observed ingestion of a potential foreign body. Significant hematological and biochemical abnormalities were found in five dogs [see Table]. A lateral thoracic radiograph was diagnostic for an esophageal foreign body in all 14 dogs; other radiographic findings varied [see Table]. Endoscopic attempts to remove or advance the foreign body failed in all 14 dogs.

Thoracic radiographs gave an accurate indication of the required location for the thoracotomy in all of the cases. Left lateral thoracotomies were performed at the fourth (n=2), fifth (n=1), seventh (n=2), eighth (n=8), or tenth (n=1) intercostal space. Esophageal perforations were identified in five dogs (case nos. 2, 3, 5, 11, 12) and ranged in length from 1 mm to 3 cm. Of the dogs with esophageal perforations, three (case nos. 2, 5, 11) had elevated total white blood cell counts preoperatively. No evidence of perforation was present on the lateral thoracic films of four of these dogs. In case nos. 3, 5, and 11, the perforations were identified during surgical examination of exposed pleural and mucosal surfaces. In case no. 12, the esophageal perforation was identified on esophagoscopy. Seven days after ingestion of a bone, case no. 2 was presented in a collapsed, hypothermic state of severe shock. Preoperative radiographs of this dog showed a pneumomediastinum as well as pleural and mediastinal effusions. The esophageal perforation (>2 cm) was identified on esophagoscopy.

Bones (n=11) were the most common foreign bodies found. Other foreign bodies included a hide chew toy (case no. 4), a fishhook (case no. 12), and a carrot (case no. 14). Thoracostomy tube drains were removed within 24 hours in 11 dogs, after 48 hours in one dog (case no. 9), and after 72 hours in one dog (case no. 6). Three dogs (case nos. 2, 6, 9) had pleural effusions present at surgery. Analysis was performed on case nos. 6 and 9. Cytology in both of these cases showed a predominance of nondegenerate neutrophils, and reactive mesothelial cells were also noted. No intra- or extracellular organisms were seen. Culture was negative in all cases.

Two dogs (case nos. 4, 6) experienced postoperative complications. Case no. 4 developed a pyothorax that was diagnosed on the 5th postoperative day. No esophageal perforation was identified in this dog at the time of surgery. Serosanguineous fluid was removed after placement of a second thoracostomy tube 5 days after surgery. Repeat esophagoscopy performed on the 5th postoperative day showed a healing mucosal esophagotomy wound, without gross evidence of perforation. Cytological analysis of the pleural fluid identified the presence of cocci, and a bacterial culture yielded Staphylococcus spp. The pyothorax was managed by drainage of fluid via the thoracostomy tube and giving amoxicillin/clavulanate^k (12.5 mg/kg per os [PO] q 12 hours) and metronidazole^l (20 mg/kg PO q 12 hours) based on culture and sensitivity results. The thorax was drained three times daily, and the tube was removed on the 9th postoperative day.

One dog (case no. 6) developed a 10 cm-diameter subcutaneous seroma on the left lateral thorax 10 days postoperatively. The seroma resolved without drainage. One dog (case no. 2) was euthanized at surgery. The 13 remaining dogs began eating within 3 days of surgery. Dogs remained hospitalized for 2 to 10 days (mean 5.2 days). One dog was discharged after 48 hours because of its fractious nature. A repeat esophagoscopy on the first eight dogs surviving surgery showed healing of the mucosal incisions in all cases. The second endoscopies were performed 2 to 14 days (mean 6.6 days) after surgery.

Eleven owners were contacted by telephone after discharge from the hospital, and all 11 dogs were clinically normal. Two dogs were lost to follow-up. Mean follow-up times for the 11 dogs was 15 months. Overall, transthoracic esophagotomy allowed removal of the foreign body and a complete return to normal function in 13 (93%) of the dogs.

Discussion

The clinical features of esophageal foreign body entrapment in dogs and its diagnosis are well documented in the literature.^1–6 History, clinical signs, thoracic radiography, and esophagoscopy are keys to the diagnosis of esophageal foreign body entrapment.^1,3 The clinical findings of dogs in the study reported here are generally consistent with previously published cases. The mean age of 5 years was higher, however, than the previously reported age of ≤3 years.^4–6 One previous study reported a mean age of 4.9 years.²

Contrast esophagraphic assessment was not used to assess the presence of esophageal perforation because of the potential for false negative results, especially when a foreign body is present.^8,9

Controversy exists as to the indications for transthoracic esophagotomy and the ideal surgical technique to use in the management of esophageal foreign bodies. Knight advocated surgical management by transthoracic esophagotomy as the first choice of treatment and reported a survival rate of 85%.⁴ Subsequent papers have advocated nonsurgical methods of removal prior to any surgical intervention.^1,2,5,6 It is possible that Knight recommended esophagotomy retrieval as a first choice because flexible endoscopy was not well developed at that time.⁴ All cases in dogs managed by transthoracic esophagotomy in subsequent reports had a combined survival rate of 70% (47/67), with a survival range of 43% to 100%.^1,2,6 The nonsurgical cases from these three studies had a survival rate of 91% (142/156).^1,2,6

Esophageal surgery has had a greater incidence of incisional dehiscence than surgery on other portions of the alimentary tract.^3,10 Several factors may contribute to dehiscence, including a lack of serosa, a segmental blood supply of the esophagus, and a lack of omentum, as well as movement and tension at the surgical site.^3,10 Successful esophageal surgery can be accomplished, however, with adherence to specific surgical principles such as gentle tissue handling, appropriate selection and application of suture materials, and accurate apposition of the tissues.^3,11,12 The rich plexus of anastomosing vessels that forms the intramural blood supply supports long segments of esophagus, and damage to it is associated with ischemic necrosis at the esophageal incision.^3,13–15

In general, the indications for transthoracic esophagotomy are a foreign body that is immovable via one or more nonsurgical methods, the presence of a large esophageal perforation, or the presence of large areas of esophageal necrosis.^1,2,5,6 The definition of a large esophageal perforation or large area of necrosis is not well documented. Some esophageal perforations heal spontaneously.^6,16 One study showed that esophageal perforations up to 12 mm in length healed spontaneously.¹⁶ Some studies showed that esophageal perforations operated after a delay of 48 to 72 hours following perforation had higher mortality rates than if managed nonsurgically with medical therapy alone.^8,17 Recent clinical studies on humans have advocated primary repair, without regard to the time interval.¹⁸ In the study reported here, three of four dogs with perforations had foreign bodies present for >72 hours before surgery, and yet these dogs had successful outcomes. When the perforations actually occurred, however, could not be determined.

Esophageal wound dehiscence or leakage, pyothorax, and pleuritis with hydrothorax are the most frequent causes of death in previous studies of transthoracic esophagotomy. Twenty-two of 37 postoperative deaths (following 159 procedures) (a survival rate of 77%) were attributable to these causes.^{1,2,4–6,8,19} In the study reported here, the only death was a dog (case no. 2) with pyothorax, mediastinitis, and pleural effusion. This dog was euthanized at surgery, and a survival rate of 93% was recorded. Surgical technique is likely to be an influencing factor on these complications, especially when preexisting contamination or infection of thoracic structures is minimal, and any complications are subsequently a consequence of intraoperative contamination or postoperative esophageal wound dehiscence. The reported thoracotomy techniques used previously varied or were not described. Thoracotomy employing a partial rib resection was described in the earlier studies by Knight, Pearson, and Houlton et al., whereas no detail on type of thoracotomy was given by Ryan, Parker, Spielman, or Bellenger et al.^{1,2,4–6,8,19} Intercostal thoracotomy with the employment of Finochietto rib retractors gave adequate exposure for all procedures in this study.

Reported details vary regarding the technique of esophagotomy type and location with respect to the foreign body. Older reports described making the longitudinal incision over the foreign body. Houlton et al. described making a longitudinal incision just caudal to the foreign body.¹ Spielman, Ryan, and Bellenger et al. do not describe an incision technique.^2,6,19 The results reported here show that a dorsal or left lateral longitudinal esophageal incision can be made overlying the foreign body. Three studies described the esophageal closure techniques used for transthoracic esophagotomy: a nonabsorbable suture with a simple interrupted pattern (in seven procedures) and a double-layer simple continuous suture pattern in the mucosa-submucosa and adventitia using 3/0 catgut (in 124 procedures).^1,3,4 An in vivo study evaluating esophagotomy closure in healthy dogs undergoing esophagotomy, comparing double-layer appositional techniques with two single-layer appositional techniques, concluded that the double-layer (simple interrupted) appositional technique was the technique of choice, resulting in the greatest immediate wound strength and best tissue apposition and healing.²⁰ A double layer of two continuous suture patterns (as used in the cases of this study), using a monofilament suture with little friction between itself and the tissue, has the advantages of distributing the tension equally along the entire length of the incision and resisting dehiscence as well as simple interrupted sutures do.²¹ Slowly absorbable suture materials have been recommended for esophageal closure in dogs.³ However, substantive fibroplasia was reported at 4 days in the submucosa of normal dogs, indicating that a more rapidly absorbed suture could be used in this layer.²⁰ Polyglactin 910 is cited as a suitable suture material in the submucosa-mucosa in humans.¹⁸ The technique used in the 13 completed surgeries in this study combined a minimally reactive monofilament, a more rapidly absorbable suture in the mucosa-submucosa layer, and a more slowly absorbable suture in the adventitia. Glycomer 630 was preferred in the muscularis/adventitial layers because of its slower absorption rate, and this was considered more suitable for the time scale for organized fibrous tissue to form in the muscularis layer of dogs in the in vivo study.²⁰ The choice of a left thoracotomy for esophagotomy at intercostal space 4/5 (case nos. 5, 8, 12) as opposed to a right thoracotomy was made, because the dorsal esophagus is readily accessible without tracheal obstruction and is nearer to the left thoracic wall than the right.

Recommendations vary regarding the best time to remove a thoracostomy tube after thoracotomy. In the study reported here, the protocol for immediate removal of the thoracostomy tube (except in those dogs with preexisting pneumothorax or pleural effusion) was established from the authors’ clinical experience of nonproductivity of thoracostomy tubes left for longer time periods before withdrawal. The authors acknowledge the controversial nature of this protocol. However, previous studies of transthoracic esophagotomy removal of foreign bodies give little detail on the protocols for use and removal of thoracostomy tubes. Immediate postoperative removal of the thoracostomy tube (in one of seven cases) and removal 1 hour after surgery (in one of seven cases) were described in one study.²³ In another case (one of seven cases) of the same study, the presence of a thoracostomy tube for 72 hours failed to give indication of successful therapy to serious complications. One recent study of nine dogs undergoing thoracotomy reported immediate postoperative removal of thoracostomy tubes without complications.²³

Conclusion

Fourteen dogs with foreign body obstruction of the esophagus had the obstructions relieved via transthoracic esophagotomy and removal of the foreign body. Clinical results were considered good in 13 dogs, two of which had postoperative complications. Based on the results of this study, esophagotomy is an effective surgical technique and can be performed with good outcomes.